Railway-traffic-controlling apparatus



March 3'1. l925.

Amplifier G. W. BAUGHMAN RAILWAY TRAFFIC CONTROLLING APPARATUS FiledOct. 10, 1924 |NVENTOR f F5 1 ATTORNEY Patented Mar. 31, 1925.

UNITED STATES I 1,531,834 PATENT OFFICE.

GEORGE W. BAUGHMAN, O'F EDGEWOOD BORQUGH, PENNSYLVANIA, ASSIGNDR TO THEUNION SWITCH & SIGNAL COMPANY, OF SWISSVALE, PENNSYLVANIA, A CORPO-RATION OF PENNSYLVANIA.

RAILWAY-TRAFFIC-CONTROLLING APPARATUS.

Application filed Qctober 10, 1924. Serial No. 742,841.

To all whom it may concern:

Be it known that I, GEORGE lV. BAUGH- MAN, a citizen of the UnitedStates, residing at Edgewood Borough, in the county of Allegheny andState of Pennsylvania, have invented certain new and useful Improve--ments in Railwayllraffic-Controlling Apparatus, of which the followingis a specification. I

My invention relates to railway trafiic controlling apparatus, andparticularlyio apparatus of the type comprising train carried governingapparatus controlled by energy received from the .trackway. Morespecifically, my present invention relates to the trackway portionof'such apparatus.

I will describe one form of apparatus embodying my invention, and willthen .point out the hotel features thereof in claims.

The accompanying drawing is a diagrammatic view showing one form ofrailway traflic controlling apparatus embodying my invention.

Referring to the drawing, the reference characters 1 and 1 designate thetrack rails of a stretch of railway track. These rails are divided, bymeans of insulated joints 2, into a plurality of tracksections, of whichonly one section, AB, is shown in the drawmg. 7 Each track section isprovided with a source of track circuit current, here shown as a tracktransformer designated by thereference character T with an exponentcorresponding to the location and having a secondary winding 5 connectedacross the rails adjacent the right hand end of the section. Animpedance 6, here shown as a reactor, is interposed between thesecondary 5 of each track transformer T and one rail 1 of the associatedsection. The primary *1- of each track transformer is constantlysupplied with alternating current from a suitable source such as analternator Mover line wires 3 and 3".

Each section is further provided with a track relay designated by thereference character R with an appropriate exponent .and connected acrossthe rails adjacent the left hand end of the associated section. Theserelays may be used to control traffic governing means not shown in thedrawing in any desired manner.

Means are also provided for supplying section AB with a loop currentwhich flows through the rails of the section in parallel. For this.purpose I connect an impedance 11 across the rails adjacent the lefthand end of the section and a similar impedance 12 across the railsadjacent the right hand end of the section. As here shown the oppositionoffered by impedances 11 and 12 is largely due to their ohmicresistance. The immediate source of loop current for this section is aloop transformer L having the terminals of its second ary 9 connectedwith the mid points of impedances 11 and 12. The primary 8 oftransformer L is supplied with alternating cur rent from line wires 3and 3", over a'front contact 7 of track relay' R It follows that whenrelay B is energized, that is, when the section to the right of point Bis unoccupied, section A-B is supplied with loop current.

The section to the left of point A is occupied by a train indicateddiagrammatically at V. Located in-front of the forward axle of thistrain are two magnetizable cores 16 and 16 provided with windings 17 and17*, respectively. and one located in inductive relation witheach trackrail. VVindings 17 and 17 are connected in series in such manner thatthe voltages induced therein by alternating currents flowing inoppositedirections in the two track rails at an instant are additive. The twowindings 17 and 17 deliver current to winding 18 of an induction motorrelay K. Located at some other convenient place on the train, such-as inrear ofthefirst axle, aretwo other cores 19 and19 carrying windings20and 20 respectively and one locatedin inductive relation with each trackrail;v The two windings 20 and 20 are connected in series in such mannerthat voltages induced therein by alternating currents flowing in thesame direction in the two track rails at an instant; are additive andthese "windings-serve to supply current to winding 21 of relay K.Suitable amplifyingapparatus '25 may be interposed between each windingof relay K and the receiving apparatus on the train.

In addition to the two windings 21 and 18, relay K comprises a rotor 22and a contact. system comprising a contact 23 controlled thereby. Thisrelaynmay be used to control train governing apparatus not shown in thedrawing, in any desired manner. When that this optimum phase relation is90. The

torque of a relay of this type increases with increases in the sine ofthe phase angle and also, of course, with increases in the currentthrough either winding.

It will be seen that the track circuit current traverses a reactor 6whereas the loop current traverses resistances 11 and 12 which aresubstantially non-inductive, and as a result the loop current and thetrack circuit currents would ordinarily be displaced in phasesubstantially 90.

I have found, however, that in long track sections a portion of the loopcurrent leaks away from the rails at one end of the sec tion, traversesthe ground instead of'the rails, and returns to the rails at the otherend of the section. As a result the magnitude of the loop current nearthe center of the section is considerably smaller than adj'a'cent theends of the section, and, moreover, the loop current near the center ofthe section lags behind the loop circuit voltage by a considerableamount. The phase angle between the loop and track circuit currents I istherefore diminished and the operation of the relay K is rendered lessreliable.

To overcome this undesirable condition I connect an impedance comprisingtwo reactors 10 and 10 in series across the rails adjacent the left handend of the section and connect the left hand terminal of primary 8 ofloop transformer L with the common point a? of these reactors. I alsoconnect the right hand terminals of primary 8 and secondary 9 together.By properly proportioning the reactors 10 and 10 the loop current may bemade to lead the loop volt I age and thereby to counteract the lagcaused by leakage through the ground.

The parts are so proportioned that the optimum phase relatlon betweenthe loop" and track circuit currents is obtained near the center of thesection. At the ends of the section, then, the loop current will leadthe applied voltage, and the track circuit current will lag behind theapplied voltage by. approximately 90. The phase angle will, then, at theends of the section, be less desirable than the optimum, but at the endsof the track section the loss due toleakage through ground is a minimumand the magnitude of the current 1n the rails at those points issufiicient to insure reliable operation of the relay.

It follows that with my invention the operation of the relay is morereliable, and that safety of operation may be insured with less power,than would be the case were the loop current not shifted to lead thevoltage. I

Although I have herein shown and described only one form of railwaytraffic controlling apparatus embodying my invention, it is understoodthat various changes and modifications may be made therein within thescope of the appended claims without departing from the spirit and scopeof my invention.

Having thus described my invention, what I claim is:

1. In combination, a stretch of railway track, a transformer, a loopcircuit including the rails of the stretch'in parallel and the secondaryof said transformer, means for supplying energy to the primary of saidtransformer, and means for connecting one terminal of said primary withone terminal of the secondary and for connecting the re maining terminalof said primary with the rails of said stretch.

2. In combination, a stretch of railway track, a transformer having aprimary and a secondary, means for supplying said primary withalternating current, and means for supplying current to the rails of thestretch in parallel from said primary and from said secondary.

8. In combination, a stretch of railway track, a transformer having aprimary and a secondary winding, means for connecting one terminal ofeach of said winding with the rails of the stretch, means'including animpedance for connecting the free terminal of said primary winding withthe rails, and means including a secondimpedance having a power factordifferent from the power factor of said first impedance for connectingthe free terminal of the secondary winding with the rails of thestretch.

4. In combination, a stretch of railway track, a transformer having aprimary and a secondary winding, a first impedance connected across therails adjacent one end of the stretch, a second and a third impedanceconnected across the rails adjacent the other end of the stretch, meansfor connecting one terminal of each winding of said transformer with thesaid first impedance, and means for connecting the free terminals ofsaid primary and secondary windings with said second and thirdimpedances, respectively. i

5. In combination, a section of railway track, a source of alternatingelectromotive force, means for supplying to the section a track circuitcurrent which .lags such electromotive force by substantially 90, meansfor supplying the rails of the section with loop current Which leadssaid electromotive force at the ends of the section, but the magnitudeof which loop current is diminished and the lead of Which loop currentWith respect to said electromotive force is decreased near the center ofthe section, due to leakage of current through the ground, and traincarried governing means including a relay having a torque whichincreases With increase in the magnitude of either track circuit currentor loop current and also with increase in sine of the phase anglebetween said currents.

6. In combination, a stretch of railway said transformer With the railsof the stretch, a resistor connected across the rails of the stretch andhaving its mid point con nected with the free terminal of saidsecondary, and two reactors connected in series across the rails of thestretch and having their common point connected With the free terminalof said primary.

In testimony whereof I aflix my signature.

GEORGE W. BAUGHMAN.

